>> they're going to check out his friends, his family, acquaintances, anybody at all who he may have had contact with in the last year, to find out, okay, have you had any contact with this guy? has he been using any kind of credit cards, atm card? has he been texting, twittering, on facebook, e-mails? >> day four, still no sign. big bear continued to be ground zero in the hunt for christopher dorner. that evening the los angeles police department announced a new investigative strategy, a joint task force. >> inside our task force are officers from the los angeles police department, the irvine police department, riverside police department, the fbi, the u.s. marshalls service and other allied law enforcement agencies throughout southern california and throughout the region. >> day five, sunday, dorner remained on the loose.